Chronic progressive, macrocytic anemia caused by a deficiency of intrinsic factor; the result is abnormally large erythrocytes and hypochlorhydria (a deficiency of hydrochloric acid in gastric secretions)

Characterized by neurologic and GI symptoms; death usually results if untreated

Lack of intrinsic factor is caused by gastric mucosal atrophy (possibly due to heredity, prolonged iron deficiency, or an autoimmune disorder); can also result in clients who have had a total gastrectomy if vitamin B12 not administered

Usually occurs in men and women over age 50, with an increase in blue-eyed persons of Scandinavian descent

Pathophysiology

Intrinsic factor is necessary for the absorption of vitamin B12 into the small intestine.

measures absorption of radioactive vitamin B12 both before and after parenteral administration of intrinsic factor

definitive test for pernicious anemia

used to detect lack of intrinsic factor

fasting client is given radioactive vitamin B12 by mouth and nonradioactive vitamin B12 IM to saturate tissue binding sites and to permit some excretion of radioactive vitamin B12 in the urine if it is absorbed